<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>外边距-合并现象</title>
  <style>
    .one {
      width: 100px;
      height: 100px;
      background-color: brown;
      margin-bottom: 80px;
    }

    .two {
      width: 100px;
      height: 100px;
      background-color: orange;
      margin-top: 50px;
    }
  </style>
</head>
<body>
  <div class="one">one</div>
  <div class="two">two</div>
</body>
</html>